Degreasing



Dec. 14, 1948. J. J. SKELLY ETAL 2,456,335

' nnenmsme 3 Sheets-Sheet 1 Filed Aug. 20, 1946 INVENTORS -194M515 J .S/(ELL TTOENEXS Dec. 14, 1948. J -IJ. SKELLY El AL DEGREASING 3 Sheets-Sheet 2 Filed Aug. 20, 1946 mimm mvm 5 1 .r Maw M 4 ML M Dec. 14, 1948.

Filed Aug. 20, 1946 J. J. SKELLY ET AL DEGREASING 3 sheds-sheet s INVENTOR.

JAMES J. SKELL Y &

ELDON K PALJTON nf/ YMZT DEGREKSING.

s flameszrhskelly, lclevelaml licights aandrllldonK.

., .icorporation ioigflhio "acclaim.

This invention relatesrto :deB-reaalng;;annd more particularly:to.animprovednnethodmt.controlling the ;heat em loyediinidesreasingi and to a novel heatzcontrolling systemrthereior.

mime customary manneriotde reasin fmrticles i ate-be. e1eaned;areiimmersedhinlahody oievaporized solvent-which condenses .onithe. artlclesandiruns 1 off, taking: oil grease andithe rlikewith-it. .JThe body of ivaporcis developed by lheating ;.and. vaporrizingiatliquid solvent. v Heatmust-ibesuppliediat airelatively highrate .to-idevelopa-the .bodysofivapon Tonmaintain the :body oi vapor, a relatively small amountpfheat is required; Hand y ifwexcessive vidleatcisHsupplled solvent iwilhbe .lost. v 'Whena'workmiece is introducediintowtheiyapor, ashighrateqof .heat supply issnecessary .to prevent-smile reduction of the bodyuof vapor zbywondensation.

The conventional approach.tof; ithis problem hasbeenfico employaihizhecapacitylheater, which i is energized .andndeenerel zedmin. a.ccordance with fluctuations inlthe .lvolumegofethe' Lbojdy of vapor .tomaintaLin thesame; approximately constant invsofaiu-as possible.

; Thisiprior artimelthodmas'been carried'nntby em loying .degneasingimachlnesccmpxisin altank l1aving.a;heater or?heatersttnjthebottonithereof,

.a vapor chambemnitheuppermofiiondithetank,

1 and a carrierwforrthe-supportfofi'the work'within such chamber.

v. lnrdegreasersioifithisicharacter, someitypes use a thermostat located withinfthemtahki to regulate the maximumeheig'htiito whichijthehsolvent vapor can rise. 'Whena liegncaser gthis type "is operating at full capacity 110': theheatersfthejfunc-o tioning of the ,thermostaticausesffthe .vapor level to fluctuate frequently... 5. Such rapid ,andifrequent .changes of vaporheightigreatlvrjincrease-the solvent losses. from 'the 'iopenptop. ofgtheutank.

' The present invention..,.conte nplates. first supplyingheat, to;theizsolventtcontlnuously,at a .high ,rate to ,developfthehndyi o'fivanor; second, supplying heat ,continuouslmor substantially so, atallow .rate. to, maintain the vvapo'r .hodviithu s. -.avo1di ng fluctuationsiof vanorconditiom'.lthlr,d,rsup'plying- V lieat.continuous'ly. at alhieh; rate when an, article to be cleaned is intmduced intoithehsolventvapor;

. and .fourth reduclngitthexrate .pof cheatesupply t0 .thelow. level .aga'in whenithe condensation Jefiect of. the articlemaslbeen overcome.

. v.;Cn,- orderitoiacllitatextheidegreasmg operatlon vin accordance withptheimethodiputlined lthis .ln- .ventiontalso contemplates a novel,,.s stem or meat icontrolioria.degreasingmachme which willautoematically .re'ducelithe lheatflnputai after -'th'e?inttial 5 machineandmechanismiassociated therewith for j .the:- automatic control .L-th-ereof tin response to vithermalichanges in Y thevsolvent vapor, the: mark thereimthediquid solvent mixture;'or .theenvlmns .of the degreasingmmachine. In detail, thecontrol system performs the following functions: When ','ithe-.-machine -1- is {idle and all. .partsxthereof mld,

, ;;the initial operation of the electric system-mill Hicausathevsolvent to :be heated at the maximum rate-.until-the correct vaporilevel is attained thus ll: conditioning t the machine ff or @operation in :the

shortest practicable time. Thereafter e-theehctrio circuit is automatically.readjusted to =mainstain the machine inrastand-iby condition with the vapor level at then-requisite point-vuntili-theimork For articles to, {be cleaned are (immersed, into the vapor bath. z Inthestandbycondition-certain ofthe heaters nzareturned off. The thermalfioutputxof the heaters remaining in operation iscalculatedioinflset 25- the heat .losses when the vapor1reachesi'aizlevel immediatelybelow. thezposition ofctheL-thermostat disposed within the tank. 'This results in-ai balanced. vapor level :having little -,tendency .itozflucwtuate inz-height, yet isubject to control gbyfluthe vthermostat if conditions such-ashigh roometsm" vpez'aturieior temporary-high voltage shouldetend unto/raise.thevaporabove thedesiredlevel.

...W-hen articles are suspended in .the man-l: ziior --d,eg11easing, itfi'iS onlyxnecessary. zforsthe qpfl fator a to press a: button to .efiect ,capaci-ty operatloneof atheiheaters and thus (rapidly restore ;the,-:l0.wered i. (vaporlevel ,resultingsfrom theheat transfer ato the relatively scold, articles introduced i into @the idegreasing chamber. :IJpon restoration ,of1-.,. ;the svapor' level the machine reverts to. its stand-by v,tcondition. --A signal light .controlledhhy lthapsystem indicates thesp'eriod .during. which the-beak .7 ers arec in..iull= operation, thus:- a prizln -nthe .,opera.tor vvhenthe iwarming yup period) of the :sol-

lventihasibeen ucompletedvand ialso indicatingz-the completion. of. the degreasing operation ,onwork in. process.

calls a safetyiieature, the control system also ,incorporates ,thermostaticemeans to out put the w ...:heate1-s when the temperature.oftheifiuidlinathe tank becomes. excessive, which mayv :resultirom ,econtamination or exhaustion i of o :the solvent.

thefheatersare cut out by theisafety'control, .a v-vvarning light is turned on. a

- ,It will be eseen therefore that svstcmeresuits in substantially automatic operation of the machine. It maintains the vapor at the proper level, safeguards the apparatus against overheating, signals the condition of the machine and indicates the progress of the degreasing operation. By virtue of the control, little attention and expenditure of time on the part of the operator is required, the degreasing is expedited, and the consumption of solvent and electric current is minimized.

An object of the invention is to provide an improved method of degreasing which will minimize loss of solvent and economize on heating energy.

Another object of the invention is to provide a method of degreasing involving improved adapta tion of the solvent heating to the requirements of the process.

Another object of the invention is to provide a degreaser which is semi-automatic.

Another object of the invention is to provide a degreaser which incorporates safeguards against overheating.

Another object of the invention is to provide a degreaser which is economical to operate.

A further object of the invention is to provide a degreaser with signalling devices to inform the operator of the condition of the machine.

Other objects and advantages more or less ancillary to the foregoing and the manner in which all the various objects are realized will appear in the following description, which, considered in connection with the accompanying drawings, sets forth the preferred embodiment of the invention, as to method and as to apparatus therefor.

Referring to the drawings:

Fig. l is a perspective view of a degreasing machine embodying the invention;

Fig. 2 is a plan view of the lower face of the base of the machine;

Fig. 3 is a transverse section therethrough, the

section being taken on a plane indicated by the line 3-3 in Fig. 2; and

Figs. 4, 5, 6, and 7 are wiring diagrams illustrating various stages in the operation of the control system.

The degreasing machine illustrated in Fig. 1 comprises a rectangular tank ll, having the top thereof reinforced by an angle iron l2 and the base inset relative to the bottom edges of the side walls of the tank. Current to the heaters and for the control of the machine is fed from a plug l3 through the conduit H to a control box I5 in which are housed the relays and pilot lights. A switch housing l6, mounted adjacent the control box, contains the starting and operating switches for the machine controlled by a Degrease button I! which initiates the operation of the machine and an Off" button I8 which terminates the operation. A tube I'9 mounted in sealed relation with an end wall of the tank intermediate the top and bottom thereof contains a vapor responsive thermostatic switch. The wiring from the switch to the control box is carried bottom plate 26 and is connected by wires 29 to the control box. The heater units comprise two stand-by heaters 3| and two degreasing heaters 32 which incorporate electrical resistance elements and are connected to the control box and power supply by leads 33, 34, 35, and 36. The heaters are mounted upon the bottom of the tank by clamps 36a retained by nuts 31 on studs 38 depending from the plate 26.

The structural details of the push button switch, the thermostats, their encasements, and the heaters form no part of the present invention, and since devices suitable for the contemplated functions may be obtained commercially,

' they will not be described in detail herein.

The principal elements of the control system of the present invention, as illustrated in Figs. 4 to '7, are the push button station If), a cutout relay 5!], a stand-by relay 60, a degreasing relay 10, a vapor-responsive thermostat switch 80, and the safety thermostat switch 90 mounted in the bottom of the tank. The stand-by heaters 3| are controlled by the relay 6D and the degreasing heaters 32 by the relay 10. The cutout relay 50 interrupts the operation of the heaters when the liquid solvent becomes too hot. A red indicator light 98 signals the operation of the cutout relay, and a green indicator light 99 signals the operation of the degreasing relay and heaters.

The operation of the system will now be describedin greater detail with refrence to Fig. 4 which illustrates the condition of the system as its operation is initiated by depression of the Degrease button 11. The Degrease button closes the contacts 4| and 42, which are normally held open by a spring, and in addition closes the contact 43 associated with the Off button l8. The contacts 4| and 42 remain closed only while the button I! is held depressed, but the contact 43 is retained in its closed position by a ball detent mechanism 44 until opened by depression of the Oil button I8. On closure of the switch IE, all of the relay-s are energized and both sets of heaters are turned on. The cutout relay 50 is energized through a circuit from the supply conductor 45 through contacts 43 and 42 in series, the conductor 41, the relay coil 5|, conductor 54, and the safety thermostat 90 to the return conductor 46. Relay 5D completes a holding circuit from the supply 45 through contact 43, conductor 48, its forward contact 52, the relay coil 5|, conductor 54, and the safety thermostat. The relay 50 will remain energized through this circuit until the Off" button is pressed or the safety thermostat contacts 90 open.

The stand-by relay 60 is energized by a circuit from the conductor 45 through contacts 43 and 42 in series, the conductor 41, relay coil 6|, conductor 64, and vapor thermostat to the return conductor 46. The relay 60 closes its forward contacts 62 and 63, thereby completing parallel circuits from the supply conductor 45 through the stand-by heaters 3! to the return conductor 46. Upon release of the push button I1, the relay 6|] is held by a circuit from the supply 45 through contact 43, conductor 48, front contact 52 of the cutout relay and conductor 41.

The degreasing relay I0 is energized by a circuit from supply conductor 45 through contacts 43, 42, and 4| in series, the conductor 49, coil H of the relay, conductor 64, and the vapor thermostat 80 to the return conductor 46. When energized, the relay [0 closes its forward contacts H and 12 to energize the degreasing heaters 32 through parallel circuits from' the supply 45 thermostat 80.

through'a contact T l o'r H -to thereturnflfia The relay 1n alsoclosesits iorwardpontact 13; completing a holding circuitk from thesupply- 45 throughcontact-fl'; conductor 48} contact 52 of the cutout relay, conductor 41; contact- 13, conductor 49; relay coil H conductor 54'; and the vapor thermostat-80'} The green pilot light 99 is i also energized by the degrea'sing relay through a circuit comprisingconductor-'45; conductor 14; and forwardcont'act H The pilot light" 9'9 'is thus incandescent wherever the degrea'sing" heaters areinoperation.

Upon release ofthe'push button IT, contacts Al and 4-2 are opened; but do not" affect theoperation of the apparatus,--since the contact- 42 is shunted by" the forward contact of the cutout re layand the contact 4 isshunted by the" forward contact-l3 of the 'degr'ea'sing relay; The heating of the solvent continues-with all therelays energized, all the heaters in operation,- and the green pilot light energized. The ope'ration of the machine may of course be stoppedwhenever'desired by opening contacts 43 by means of the Off button l8 deenergizing theentire apparatus.

Normally, however, the condition'of the apparatus remains as illustrated in Fig; 4 until the solvent is heated sufficientlyfor therising vapor to heat the vapor thermostat wand cause it to open its contacts. When this occurs, as illusgized, since its circuit-iscompleted-through-the I safety thermostat 9'0 rather than the vapor Deenergization of 5 the relays 60 and 10 interrupts the supply of current to the stand-by heaters 3|; the degreasing heaters 32, and the green pilot light 99'. Extinction of the light indicates that the machine is ready to re ceive the work. The holding circuit for the degreasing relay is also opened at its contact 13.

Withthe heaters off, the solvent will cool, the vapor will begin to condense; the levelthereof rill belowered, and the'vapor 'ther'mostat 80 will close its contacts. When this happens, as inastrated in Fig. 6, the energizing circuitofthe stand-by relay is completed from conductorthrough contact 43, conductor 48; contact 52", conductor 41, relay coil 61-, conductor 64, and the thermostat 'to the returnconductor 4G; andthe stand-by heaters 31 are energized-'asbefore. The degreasing relay 'm will not operates-inee its energizing circuit is open at contacts 42 and 4| and its hoding circuit-is openat contact"; therefore, the degreasing heaters 32 remain outofoperation. The stand-by heaters are sufiicient to maintainthe vapor level in-theabsence'of condensationfrom objects being degreased and serve to maintain the machine in its stand-by condition; that is, with-the vapor at the requisite temperature to receivethework. If; because of high atmospheric temperatures or high line voltage, the vapor rises too highin'the tank,.the thermostat 80 deenergizes the relay '60 and the stand by heaters are cutout untilthe vapor level falls. This stand-by condition is maintained until it is desired to perform a degreasing-operation.

Whenever the'operator desirestodegrease an article, he'suspends the work in the tank below the vapor level in the usual'manner and again presses the Degrease button l1, energizing the degreasing relay (0. The degreasingrelay'rnaine tains its holding circuit closed through the: forward contact 13 and energizes the: degreasmt v by the combined effect oi both sets: of

the vapor thermostat 80- opens its contacts and the machine reverts to the condition illustrated ins-fig; 5. Both: sets oiilieaters aradeenergiwi and the green pilot. light: is extinguished, indicating the completion of the' deg-reasing opera tion; It" will be seen that the-only operation-the operator is required to perform other? than: in setting :and removing the article-s from-the: tank is to press the De'grease 'buttomwhem the mx chine is first put into operation: and when the articles areplaced inathe-tank.

If for any reason the solvent' in the tank should become overheated,.the safety features. of the control system are broughtlinto operation,- as ib lustrated in- Eig. 7; Overheating oi the: fluid causes the safety thermostat contactsto op'en. The cutout relay 50, which has been: held-'by--'a circuit from conductor 45 through contact 43 conductor 4'8g fr0ntcontact 52'; conductor: 54, and safetythermostat 90 t'o-conduct'or isthu's daenergized; The'holdingcircuits'of th'e stand by relay B8 anddegreasingreiay 10 are opened at contact 52 and-therefore the heaters are cutout. Upon deenergization of the cutout; relay, it'scom tact 53 closes, completing: a-- circuit f'ro'mconduc= tor 4'5'through contact 43} conductor' contact 53,- conductor 9|; and the redp'ilot'light 98 to com ductor. 46'. The red-pilotlight remains energized; indicating" to the operator'that the circuit has been cut out and requires attention; until: the Off button H3: is pressed to opencorit'act-4."'

A condenser 92 (Fig. 7) is bridged acrossconductors 54"and'64 to minimize arcinggof' the com tacts of'the thermostats whenthe contacts open;

Although the foregoing description is necesa sarily of adetailed characterg in order that the invention maybe completely'set forth; it'- is-t'o be understood that th'e" specific terminology is not intended t'o be restrictive-or confining, and that various rearrangements. of: parts and modifications of: detail may be resorted to'without departing from the scope or spirit ofthe invention as herein claimed,

For example, instead of two separate heaters; a single heater operable-attwo differentenergy levels; may. be: employed; Electric heaterscom nectable in either series or parallel relationmay be used. Also, other heatingme'diums than elec tric heaters,- such a's gas flames and steam. coils may be employed by installationof valves therefor controlled by relays as shown: herein, or equivalent control devices,- as: will be obvious' to thoseskillediin the art.

1:.uA de'greaser comprising a t'anh'lfor contain ing a solvent; a stand -by1 heater; an degreasin'g heater, a thermostat aifected by solvent va'por, means for initiating operaticn o'f both heaters, lockout means controlled by: the thermostat: for terminatingoperation of the degreasing heater, means for. deenergizing the heaters; and means controlled by the. thermostat for" regulatingthe operation of the stand-by heater until the d energizing: means iso'perated.

l 2. A deg-reas'eroomprising'vatank for conta'im ing: a: solvent; a: stand-by heatera decreasing heater, a thermostat aflec'tedi by solventrvapor,

means for initiating operation of both heaters, lockout means controlled by the thermostat for terminating operation of the degreasing heater upon generation of a predetermined quantity of vapor, means for deenergizing the heaters, and means controlled by the thermostat for regulating the operation of the stand-by heater to maintain the quantity of vapor at the predetermined value, until the deenergizing means is operated.

3. A degreaser comprising a tank for containing a solvent, a stand-by heater, a degreasing heater, a thermostat affected by solvent vapor, means for initiating operation of both heaters, lockout means controlled by the thermostat for terminating operation of the degreasing heater, means for indicating operation of the degreasing heater, means for deenergizing the heaters, and means controlled by the thermostat for regulating the operation of the stand-by heater, until the deenergizing means is operated.

4. A degreaser comprising a tank for containing a solvent, a first heater, a second heater, a thermostat responsive to the solvent vapor, a first relay for energizing the first heater, a second relay for energizing the second heater, a switch having a holding contact and a normally open contact, an energizing circuit for the first relay including the holding contact and the thermostat, a first energizing circuit for the second relay including the normally open contact and the thermostat. and a second energizing circuit for the second relay including the holding contact, a front contact of the second relay, and the ther mostat, whereby both heaters are energized when the switch is operated, the second heater is cut out when the thermostat operates and remains cut out, and the first heater is operated intermittently under control of the thermostat.

5. A degreaser comprising a tank for containing a solvent, a first heater, a second heater, a thermostat responsive to the solvent vapor, a first relay for energizing the first heater, a second relay for energizing the second heater, switch means including a first contact retained in either open or closed position and a second contact retained only in open position, an energizing circuit for the first relay including the first contact and the thermostat, a first energizing circuit for the second relay including the second contact and the thermostat, and a second energizing circuit for the second relay including the first contact, a front contact of the second relay, and the thermostat, whereby both heaters are energized when the switch is closed, the second heater is cut out when the thermostat operates and remains cut out, and the first heater is operated intermittently under control of the thermostat until the switch is opened.

6. A degreaser comprising a tank adapted to contain a solvent, a first heater, a second heater, manually actuatable means for initiating operatlon of both heaters, a thermal control device exposed to vapor rising from the solvent, lockout means responsive to the thermal control device for terminating operation of the second heater, and means responsive to the thermal control device to regulate the operation of the first heater.

7. A degreaser comprising a tank adapted to contain a solvent, a first heater, a second heater,

manually actuatable means for initiating operak tion of both heaters, a thermal control device exposed to vapor rising from the solvent, lockout means responsive to the thermal control device for terminating operation of the second heater, means responsive to the thermal control device to regulate the operation of the first heater, a temperature-responsive means exposed to the liquid solvent, and lockout means controlled by the temperature-responsive means for terminating operation of both heaters.

8. A degreaser comprising a tank adapted to contain a solvent, a first heater, a second heater, manually actuatable means for initiating operation of both heaters, a thermal control device exposed to vapor rising from the solvent, lockout means responsive to the thermal control device for terminating operation of the second heater upon generation of a predetermined quantity of vapor, means responsive to the thermal control device to regulate the operation of the first heater to maintain the quantity of vapor, a temperature-responsive means exposed to the liquid solvent, and lockout means controlled by the term perature-responsive means for terminating operation of both heaters when the solvent temperature rises above a predetermined point.

9. A degreaser comprising a tank adapted to contain a solvent, a first heater, a second heater, manually actuatable means for initiating opera.- tion of both heaters, a thermal control device exposed to vapor rising from the solvent, lockout means responsive to the thermal control device for terminating operation of the second heater, means for indicating operation of the second heater, means responsive to the thermal control device to regulate the operation of the first heater, a temperature responsive means exposed to the liquid solvent, lockout means controlled by the temperature-responsive means for ending operation of both heaters, and means for indicating the operation of the ending means.

10. A degreaser comprising a tank for containing a solvent, a first heater, a second heater, temperature-responsive means exposed to the solvent, temperature-responsive means exposed to the vapor rising from the solvent, a manual power control, a first control device for the first heater, a second control device for the second heater, means responsive to operation of the manual control for initiating operation of the control devices, means responsive to operation of the control devices for maintaining operation. of the heaters, lockout means controlled by the vapor-responsive means for terminating operation of the second control device and heater, means controlled by the vapor-responsive means for regulating operation of the first control device and heater, and means controlled by the solvent-responsive means for terminating operation of both control devices and both heaters.

11. A degreaser comprising a tank for containing a solvent, a first heater, a second heater, temperature-responsive means exposed to the solvent, temperature-responsive means exposed to the vapor rising from the solvent, a manual power control, a, maintaining device, a first control device for the first heater, and a second control device for the second heater, means responsive to operation of the manual control for initiating operation of the maintaining device, means responsive to operation of the maintaining device for maintaining operation of the control devices for causing operation of the heaters, means controlled by the vapor-responsive means for torminating operation of the second control device and second heater, means controlled by the vaporresponsive means for regulating operation of the first control device and first heater, and means controlled by the solvent-responsive means for terminating operation of the maintaining de- 11 terminating operation at the high thermal output of the heating element, and means responsive to the thermal control device for regulating the operation of the heating element at a low thermal output.

22. In combination, a tank for containing a vaporizable fluid, a first heater, a second heater, a thermostat aifected by the vapor of the fluid, means for initiating operation of both heaters, lockout means controlled by the thermostat for terminating operation of the second heater, means for deenergizing the heaters, and means controlled by the thermostat for regulating the operation of the first heater until the deenergizing means is operated.

23. A degreaser comprising a tank adapted to contain a solvent, a first heater suflicient to maintain the desired solvent vapor level when the de Breaser is idle, a second heater to increase the heating rate to counteract condensation upon a workpiece suspended in the vapor, a control device responsive to the level of vapor rising from the solvent, means actuated by the control device for terminating the operation of the second heater when the vapor rises to the desired level, and

means actuated by the control device for temporarily interrupting the operation of the first heater when the vapor rises to the desired level, the last-named means being adapted to reinstate the operation of the first heater whenever the vapor falls below the desired level.

24. A degreaser comprising a tank adapted to contain a. solvent, a first heater sufllcient to maintain the desired solvent vapor level when the degreaser is idle, a second heater, manually actuatable means for initiating the operation of both heaters, a control device responsive to the level of vapor rising from the solvent, means actuated by the control device for terminating the operation of the second heater when the vapor rises to the desired level, means actuated by the control device for interrupting the operation of the first heater when the vapor rises to the desired level, the last-named means being adapted to reinstate the operation of the first heater whenever the vapor falls below the desired level, means responsive to the temperature of the liquid solvent for terminating the operation of both heaters when the solvent temperature rises above a predetermined value, and a manually actuatable means for terminating operation of the heaters.

JAMES J. SKELLY. ELDON K. RALSTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date .Re. 20,359 Robertson May 11, 1937 1,459,049 De Khotinsky June 19, 1923 2,023,544 Pierson Dec. 10, 1935 2,061,148 Fischer Nov. 17, 1936 2,253,579 Phillips et al Aug. 26, 1941 2,329,674 Phillips et al Sept. 14, 1943 2,366,949 Woppman et al Jan. 9, 1945 2,371,646 Petering Mar. 20, 1945 

